Pitting Corrosion Behavior of Silver-Containing 2205 Duplex Stainless Steel as Secondary Austenitic Phase Existed

摘要

Silver-containing 2205 duplex stainless steel was developed to study its phase transformation, precipitating behavior, as well as corrosion resistance. The result reveals that the doping of silver in 2205 duplex stainless steel decreased the γ2 phase volume fraction. In addition, the solubility of silver in iron was extremely low, and silver particles were distributed randomly both in the matrix and on the boundaries of the material. Silver particles were observed on the material surface and the number of particles on the surface increased with the silver content. The pitting corrosion resistance of the test materials decreased with increasing silver content. The pits on the material surface became more abundant when the silver content was increased. The protective function of continuous Cr_2O_3 film on the surface of the steel was destroyed by the silver particles that weakened the pitting resistance. In addition, the initiation of pitting corrosion usually occurred around the γ2 phase, which had low concentrations of chromium and molybdenum.